460 Fuel System Page - Help Needed

[Gary Lewis]

I've created a new page on which I'm hoping we can document the ins and outs of the 460's fuel system.  It is at Fuel Systems/460 Fuel Systems.  But, I need your help!


I thought I understood it fairly well, but have proven to myself that I don't.  So I've embedded questions or statements in red that y'all need to help me with.  And, I'm sure there are things stated in there that are wrong, so please find those as well.

The main questions is: What trucks got the mechanical pump and which ones got the electric pump, and what determined that?

[grumpin]

My 1986 F250 has electric pumps in each tank, 19 gallons each. Steel tanks.

It has the "hot fuel" system. I have A/C which I understand is why it has the "hot fuel" system.

It is a non-catalyst truck, 8800 GVWR. I believe the last year for any non-catalyst trucks.

Has a 4180 Holley (Motorcraft) carburetor.

You probably already know this, but thought I would throw it in.

Thanks!

[85lebaront2]

The rule I heard was two fold, A/C and hot climate areas for the hot fuel handling package. I am reasonably certain ambulance chassis models got the hot fuel package. Non-A/C and cooler climates received a mechanical fuel pump. FWIW, all the 460s through 1987 had provision for a mechanical pump, if the hot fuel package was installed, then a block-off plate with a bracket for the fuel lines was installed in place of the pump.

1987 was the last carbureted, non-catalyst 460, 1988 is when EFI and catalytic converters started.

[grumpin]

Thanks!  

[Gary Lewis]

Bill - I updated the page with your quote.  Hope that's ok.  

[grumpin]

I asked about fuel pressure in the carb post, don't know why I didn't check my manual!  

However my truck doesn't have a Tank Selector Relay.

[85lebaront2]

1986 does not use a tank selector relay, 1985 did and possibly all the way back to 1980 on the E-series and 1983 on F-series. The 1986 EVTM shows exactly what the 1986 models did.

Fuel pressure, I knew it was pretty low, even a persnickety Carter/Edelbrock should have no problems at 4.3 psi.

[Gary Lewis]

The spec may be 4.3 psi, but that has to vary with what orifice is in the return. And, even after the return I measured 5 1/2 psi on Big Blue with the resistor in the circuit. Without the orifice the pressure is going to be more than 5 1/2, which is about the limit for an Eddy, so I wouldn’t feel comfortable w/o a regulator.

[ArdWrknTrk]

The white seperator is .090", compared to the red & blue at .045, and .065.
You might find this as a way to keep the pressure down without resorting to drastic measures.

Then again, I know nothing about return regulators.

[85lebaront2]

I have a suspicion that the pump(s) in Big Blue might be for an early EFI system, they were a bit higher to operate the selector valves.

[Gary Lewis]

Yup.  And to this day I don't know what orifice is in Big Blue.  Probably won't find out until I install the return-style regulator I have and take the hot fuel handling piece out.